Drizzle some good olive oil into the bottom of a baking pan and spread out to cover the entire pan. Layer onto this the potatoes, then the onions and tomatoes.
In a medium bowl mix 2/3 of the parsley, 2/3 lemon juice, a generous Tbs of paprika, a tsp of cumin, salt and pepper ( to taste ), 1 clove of freshly crushed garlic, and some olive oil. Mix well and rub all over and inside the fish.
Layer the fish on top of the vegetables and pour over some of the juice from the bowl they were rubbed with. Not too much though.
In a small bowl mix together the remaining lemon juice, parsley, another Tbs Paprika, 1 tsp Cumin, salt and pepper ( again to taste )and a small amount of olive oil. Fill the fish cavities with this mixture pouring the juices over the filling after they are full.
Drizzle everything with a good glug of olive oil, sprinkle on remaining Paprika, salt and pepper and finish off with a generous amount of Italian Herbs. Finally layer the Lemon slices over the fish.
Cover with aluminum foil and bake at 180 degrees for 1 hour on the hottest shelf of the oven, remove the foil and bake again for a further 30 mins or until the vegies are nice and tender and the sauce thickens.